NEW ORLEANS - BP reinstalled an oil containment system sucking up crude from a ruptured pipe in the Gulf of Mexico, which had been removed following a collision with a robotic submarine.
The oil cap "was successfully reinstalled on the Deepwater Horizon's failed blow-out preventer" at 6:30 p.m. (2330 GMT) Wednesday, BP said in a statement, adding that "the system resumed collecting oil and gas" a half hour later.
Oil spewed unhindered into the Gulf of Mexico when BP detached the "top hat" cap, which traps leaking oil and then siphons it up to a container ship, and made repairs after a remote-controlled submarine crashed into it.
The setback marked a terrible start for American Bob Dudley in his first day as BP's disaster coordinator, brought in by the firm to replace gaffe-prone British CEO Tony Hayward.
Admiral Thad Allen, leading the US government effort to confront the nation's worst ever environmental disaster, said earlier the cap had been removed for inspection after crews detected gas.
"Out of an abundance of caution ... they moved the containment cap with the riser pipe and moved away so they can assess the condition," Allen told reporters earlier Wednesday, before the cap was reattached.
"They indicated the problem was a remotely-operated vehicle had bumped into one of the vents," Allen said, adding that the vent had then closed, creating pressure that had forced up gas and other materials.
The cap is siphoning away some 25,000 barrels of oil each day, and keeping it off would have exacerbated the dire effects of the massive leak that has allowed between 35,000 and 60,000 barrels of crude to gush into the sea, according to the latest US government estimates.
Completing a disastrous start for Dudley, Allen said two people involved in the clean-up efforts had been reported dead in separate incidents.
One was killed in what he described as "an accident regarding a swimming pool," and the second individual died of a likely self-inflicted gunshot to the head, according to the local Alabama coroner who treated the body.
Dudley assumes command from Hayward, who faced massive criticism of his handling of the spill, including accusations of insensitivity, and was ridiculed as out of touch.
Unlike Hayward, Dudley is an American citizen who spent much of his childhood in Mississippi, one of the four southern US states whose coastlines face an environmental catastrophe.
The news came as administration officials pledged to redouble efforts to freeze new deepwater oil drilling while they assessed safety regulations.
On Tuesday, Judge Martin Feldman overturned a drilling moratorium authorized by President Barack Obama in the spill's aftermath, saying it was "arbitrary and capricious."
But the White House pledged to appeal the decision and Interior Secretary Ken Salazar told lawmakers at a hearing on Wednesday that he would soon issue a new order to ensure the freeze sticks.
"We will move forward with the executive authority which I have to make sure that the moratorium stays in place," Salazar said.
The Obama administration believes the decision flies in the face of mounting evidence that there are serious safety risks with the 33 deepwater wells in question.
But oil workers and executives argue the freeze is driving away business, and Louisiana Governor Bobby Jindal, a Republican, said the moratorium hurt the same people already being negatively impacted by the spill.
An internal BP document released by a US lawmaker this week showed the firm contemplated a worst-case scenario of up to 100,000 barrels, or 4.2 million gallons, a day leaking.
America's worst previous oil spill, the 1989 Exxon Valdez disaster, dumped nearly 11 million gallons off the Alaskan coast, but even under the low end of current estimates, more than 90 million gallons have entered the Gulf.
BP has spent two billion dollars so far on cleaning up the spill and compensating residents and businesses facing ruin.
The nine-week-old spill began with an April 20 explosion that ripped through the BP-leased Deepwater Horizon rig, 50 miles (80 kilometers) off the Louisiana coast, killing 11 workers.
More than 125 miles of Louisiana coast have been contaminated, shutting down fishing operations and triggering long-term fears for the region's already endangered wildlife.